Nutrients and enzymes Flashcards
Functions of H2O
- Solvent for chemical reactions in the body—> Water is the solvent for many chemical reactions in living things eg. Plants need water for photosynthesis
2.Key component of tissues —> water is a key component in cells, tissue fluid, digestive juices and blood - Helps to regulate body temperature—> When sweat evaporates from the skin surface, latent heat is removed. The body is then cooled dow.
4.Transporting dissolved substances—>water is a solvent which helps to transport dissolved substances eg. Digested products from the small intestine to other parts of the body.
In plants, water is - essential for photosynthesis
2.keeps cells turgid
3.transport mineral salts from the roots to other parts of the plant through the xylem
4.transport food substances from leaves to other parts of the plant through the phloem
Chemical elements that make up carbohydrates
Carbohydrates are made up of carbon, hydrogen and oxygen. The hydrogen and oxygen atoms are present in the ratio of 2:1
Chemical Elements that make up fat
Carbon, hydrogen and oxygen.
Chemical elements that make up proteins
Carbon, hydrogen, oxygen and nitrogen. Sulfur may also be present
Test for proteins
Biuret test
1. Add 2cm3 of NaOH solution to 2cm3 of egg white solution in a test tube and shake it thoroughly.
2. Add 1% CuSO4 solution drop by drop, shaking the mixture after each drop.
3. Shake well and allow the mixture to stand for 5mins
OR
Add 2cm3 of biuret solution to 2cm3 egg white solution.
Observation: the biuret solution will turn form blue to purple in the presence of proteins.
What makes up glycogen?
- structure
- role
- occurrence
Structure: Glycogen is a made up of many glucose molecules joined together.
Role: it is the storage form of carbohydrates in mammals
Occurrence: liver and muscles in mammals
What makes up fats?
Fat molecule—> glycerol + 3 fatty acids
What makes amino acid?
Made up of amino group, an acidic group and a side chain.
What makes up protein
Made up of chains of amino acids(polypeptides)
What is the definition of catalyst?
A catalyst is a substance which can alter or speed up a chemical reaction, without itself being chemically changed at the end of the reaction.
What is the definition of enzyme?
Enzymes are proteins that function as biological catalyst. They can alter or speed up chemical reactions. They remain unchanged at the end of the reaction.
What are the characteristics of enzymes?
- Enzymes speed up chemical reactions—> by lowering the activation energy needed to start the reaction
- Enzymes are required in minute amounts—> since they remain chemically unchanged at the end of a reaction, they can be reused over and over again.
- enzymes are specific in action—> only substrate that has a 3-D complementary shape to the active site of an enzyme can fit into the enzyme and form an enzyme-substrate complex.
How temperature affects the enzyme
Low temp—> KE is low, decreases chances of collisions between enzymes and substrates (inactive)
Optimum temp—> most active
Beyond optimum temp—> breaks bonds that keep the enzyme protein in shape, causes enzyme to lose its original shape, substrate molecules unable to fit into active site(denaturation)
For every 10°C rise in temp, rate of enzyme reaction doubles until optimum temp.
Increase temp->increases KE-> increases rate of collisions-> increases the chance of substrates fitting into enzymes-> increases formation of enzyme-substrate complex
Definition of denaturation
Denaturation is the change in the three-dissensions structure of an enzyme or any other soluble protein, caused by heat or chemicals such as acids or alkalis.
How are enzymes affected by pH?
Optimum pH—> most enzyme-substrate complex
Beyond optimum pH—> denaturation
